This invention pertains to the art of protective coatings, and more particularly to the art of protective coatings for flooring tiles containing hazardous materials. It will be appreciated, however, that the invention has broader applications and may be advantageously employed in other environments such as in connection with coating non-flooring surfaces.
Many preexisting floors contain materials which have in recent years been determined to be hazardous. Asbestos, a known carcinogen, is among the more prevalent hazardous materials found in flooring. Removing asbestos materials from existing structures has become a rather undesirable undertaking for health, safety and economic reasons. Extreme care must be taken during its removal to avoid contact or ingestion by humans.
In an effort to avoid the hazards and expense involved with removing asbestos flooring, it has become known to encapsulate asbestos-containing floors with encapsulating or coating materials having qualities which allow for safely maintaining existing flooring in place. While known encapsulating materials offer many benefits, as will be discussed below, prior art encapsulating materials are not without disadvantages.
For example many of the encapsulants for coating existing materials must be mixed or prepared at the work site. This can lead to a lack of consistency of the encapsulant, and substantially reduce the encapsulant's effectiveness.
In addition, encapsulating materials of the prior art typically require multiple steps in application. Those which have been known to require a single step application are comprised of an elastomeric polymer-moisture cured polyurethane. These, however, have proven to have a very short shelf life. Moreover, these moisture cured polyurethanes do not provide encapsulating properties until they are covered with a layer of sheet goods.
The EPA has issued a number of minimum requirements which must be met for asbestos encapsulating materials. For example, the EPA requires that asbestos fibers be sealed or locked in by either bridging over the surface, or penetrating into the matrix of the asbestos containing material. The encapsulator is not to include any toxic substances, nor should it reduce significantly the fire retardant properties of the underlying material. The encapsulating materials are to be applied with a minimum of effort and technical skill, and must have a sufficient impact resistance, flexibility, and resistance to penetration in order to withstand moderate physical contact. In addition, it is important that the resulting encapsulating composition be water insoluble once it has been cured, and that it is non-toxic and without noxious fumes during application. Finally, among the requirements set forth by the EPA, the encapsulating compound should have aging characteristics which permit it to withstand normal atmosphere changes for a minimum of six years while still maintaining sufficient surface integrity to allow recoating.
The material of the present invention meets and/or exceeds all of the requirements outlined above as propounded by the EPA.
With the above requirements in mind, it is desirable that an encapsulating material be developed which offers ease of installation, i.e., one that permits a single step application. Since the existing flooring may be uneven and full of imperfections, dents and ridges, it is desirable that the encapsulating compound be self-levelling. Also, the encapsulant should be one that will permit the installation of a new layer of flooring thereon such that it will bond with the adhesive used in installing the new flooring.
The encapsulating material should be capable of forming a continuous sheet to prevent asbestos exposure. Along these lines, the material should be sufficiently strong to prevent wear and, thus, re-exposure of asbestos.
Finally, it is desirable to develop an encapsulating material having a reasonable shelf life.
The present invention contemplates a new and improved encapsulating compound which overcomes all of the above-referred problems and others and provides a self-levelling, continuous asbestos encapsulating compound which is an economical alternative to removing existing flooring.
The formulation provides a permanent coating which adheres firmly to the surface of flooring materials to seal in any hazardous materials such as asbestos. The formulation provides a strong, water resistant, nonporous coating which does not require combination with other products before use. Moreover, the coating formulation eliminates the need to dispose of hazardous waste and does not interfere with the drying of subsequent flooring layers added thereto. The composition requires a minimal effort to spread, and minimal surface preparation before application. Finally, the product provides an easy clean up.